Float operated vent valves are commonly used in fuel tanks to close a valve port when fuel in the tank rises above a predetermined level. In an example, a float operated vent valve can be configured as a poppet-style valve that includes a seal supported on a poppet member. In turn, a float member can be attached to or operatively connected to the poppet member. Thus, when fuel in the tank rises above a predetermined level, the float member may rise with the fuel. As a result, the seal may engage a valve seat of the valve port to close the valve port and prevent the release of fuel from the tank through the valve port.
When fuel in the tank drops below the predetermined level, the float member may full from the raised position and disengage the seal from the valve seat to open the vent valve and relieve internal pressure through the valve port. However, relatively high pressure within the tank can generate internal forces that act on the poppet member, which may cause the seal to remain engaged against the valve seat even after the fuel has dropped below the predetermined level. As a result, a relatively large release force may be needed to overcome the internal pressure within the tank to release the seal from the valve seat. For example, to achieve such a release force, the weight of the poppet member and/or float member may be increased. In another example, the float member may be provided on a distal end of a lever arm that extends from the poppet member. These designs, however, tend to increase the size and/or weight of the vent valve.
Thus, although known vent valves may function in an acceptable manner, it would be desirable to provide a float operated vent valve having a poppet member configured to require little or no additional force to open the valve against internal pressure within the tank.